A new high performance computer d-c amplifier

A new computer d-c amplifier designed for very fast as well as for real-time analog/hybrid computation combines large bandwidth (30 MHz gain-bandwidth product) and high mid-band gain (68 dB at 10 KHz) with full ± 10V, 30mA output to 5.0 MHz, and low open-loop output im pedance (50 ohms at 10 KHz). High d-c gain (120 dB) and exceptionally low drift (50 pA/°C, 2.5 μV/°C) is obtained with the aid of an inexpensive hot-substrate integrated- circuit preamplifier rather than with conventional chopper stabilization. A three-channel feedforward design employs an overcurrent-protected 30 mA class AB wideband output stage in the high-frequency channel, a feedback-equalized integrated-circuit operational amplifier as the intermedi ate-frequency channel, and the hot-substrate integrated differential amplifier stage as the low-frequency channel. Overcurrent protection makes the new amplifier short- circuit proof. Table 1 shows the performance of the new d-c amplifier.